Toner, method for producing toner, two component developer, and image forming apparatus

Abstract

First toner of the present invention includes colored particles and an external additive. The colored particles are produced by heating and aggregating a mixture that includes a resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, so that at least part of the first resin particles is melted. The colored particles have a finely roughened surface. Second toner of the present invention includes aggregated particles including at least first resin particles and pigment particles, and colored particles having a finely roughed surface formed by fusing at least part of wax and at least part of second resin particles on the surface of the aggregated particles. Third toner of the present invention includes aggregated particles including at least first resin particles and pigment particles, and colored particles having a finely roughened surface formed by fusing at least part of third resin particles and at least part of fourth resin particles on the surface of the aggregated particles. When the aggregated particles are formed in an aqueous medium, the pH is controlled in the specified range. The toner can achieve oilless fixing that prevents offset without using oil while maintaining high OHP transmittance. Therefore, it is possible to eliminate the spent of toner components on a carrier and to make the life longer. Moreover, thinning or scattering during transfer can be suppressed, thus ensuring high transfer efficiency.

1 . Toner comprising: 
 colored particles; and    an external additive,    the colored particles produced by heating and aggregating a mixture that includes a resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, so that at least part of the first resin particles is melted,    wherein the colored particles have a finely roughened surface.    
     
     
         2 . The toner according to  claim 1 , wherein the colored particles are substantially spherical in shape.  
     
     
         3 . The toner according to  claim 1 , wherein a surface roughness index of the colored particles is not more than 95%.  
     
     
         4 . The toner according to  claim 1 , satisfying a relationship expressed by  
         100≦KC≦130 and  1.1 ≦BTs/BTk≦ 6.0  
       where KC is a shape factor of the colored particles, BTs is a BET specific surface area by nitrogen adsorption, and BTk is a specific surface area calculated from a particle size of the colored particles.  
     
     
         5 . The toner according to  claim 1 , further comprising wax and second resin particles, 
 wherein at least part of the second resin particles is fused on a surface of aggregated particles obtained by heating and aggregating the mixture that includes at least the first resin particles and the pigment particles.    
     
     
         6 . The toner according to  claim 5 , wherein the wax has an acid value of 10 to 80 mgKOH/g and comprises a long chain alkyl group having a carbon number of 4 to 30, an ester group, and a vinyl group.  
     
     
         7 . The toner according to  claim 5 , wherein the wax is at least one selected from the group consisting of a derivative of hydroxystearic acid, glycerin fatty acid ester, glycol fatty acid ester, sorbitan fatty acid ester, aliphatic amid having a carbon number of 4 to 30, and saturated or mono- and di-unsaturated alkylenebis fatty acid amide.  
     
     
         8 . The toner according to  claim 5 , wherein a melting point of the wax is at least 15° C. higher than a glass transition point (Tg) of the second resin particles.  
     
     
         9 . The toner according to  claim 1 , further comprising third resin particles and fourth resin particles, 
 wherein at least part of the third resin particles and at least part of the fourth resin particles are fused on a surface of aggregated particles obtained by heating and aggregating the mixture that includes at least the first resin particles and the pigment particles.    
     
     
         10 . The toner according to  claim 9 , wherein a melting start temperature of the fourth resin particles is at least 15° C. higher than that of the third resin particles.  
     
     
         11 . The toner according to  claim 9 , wherein a weight-average molecular weight of the fourth resin particles is at least 10% larger than that of the third resin particles.  
     
     
         12 . Toner comprising: 
 aggregated particles including at least first resin particles and pigment particles; and    colored particles having a finely roughened surface formed by fusing at least part of wax and at least part of second resin particles on a surface of the aggregated particles.    
     
     
         13 . Toner comprising: 
 aggregated particles including at least first resin particles and pigment particles; and    colored particles having a finely roughened surface formed by fusing at least part of third resin particles and at least part of fourth resin particles on a surface of the aggregated particles.    
     
     
         14 . A method for producing toner in an aqueous medium by heating and aggregating a mixture that includes at least a first resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, 
 the method comprising steps of:    A. adjusting a pH of the mixture of at least the first resin particle dispersion and the pigment particle dispersion in a range of 9.5 to 12.2;    B. adding a water-soluble inorganic salt to the mixture;    C. heat-treating the mixture so that at least the first resin particles and the pigment particles are aggregated to form aggregated particles, and at least part of the aggregated particles is melted;    D. adjusting a pH of the mixture at the time of forming the aggregated particles in a range of 7.0 to 9.5;    E. adding a second resin particle dispersion in which second resin particles are dispersed and a wax particle dispersion in which wax is dispersed to an aggregated particle dispersion in which the aggregated particles are dispersed and adjusting a pH of the resultant mixture in a range of 5.2 to 8.8;    F. heat-treating the mixture at temperatures not less than a glass transition point of the second resin particles for 0.5 to 2 hours;    G. adjusting a pH of the mixture in a range of 3.2 to 6.8; and    H. fusing the second resin particles and the wax with the aggregated particles by further heat-treating the mixture at temperatures not less than the glass transition point of the second resin particles for 0.5 to 5 hours, wherein colored particles produced have a finely roughened surface.    
     
     
         15 . A method for producing toner in an aqueous medium by heating and aggregating a mixture that includes at least a first resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, the method comprising steps of: 
 A. adjusting a pH of the mixture of at least the first resin particle dispersion and the pigment particle dispersion in a range of 9.5 to 12.2;    B. adding a water-soluble inorganic salt to the mixture;    C. heat-treating the mixture so that at least the first resin particles and the pigment particles are aggregated to form aggregated particles, and at least part of the aggregated particles is melted;    D. adjusting a pH of the mixture at the time of forming the aggregated particles in a range of 7.0 to 9.5;    E. adding a third resin particle dispersion in which third resin particles are dispersed and a fourth resin particle dispersion in which fourth resin particles are dispersed to an aggregated particle dispersion in which the aggregated particles are dispersed and adjusting a pH of the resultant mixture in a range of 5.2 to 8.8;    F. heat-treating the mixture at temperatures not less than a glass transition point of the third resin particles for 0.5 to 2 hours;    G. adjusting a pH of the mixture in a range of 3.2 to 6.8; and    H. fusing the third resin particles and the fourth resin particles with the aggregated particles by further heat-treating the mixture at temperatures not less than the glass transition point of the third resin particles for 0.5 to 5 hours,    wherein colored particles produced have a finely roughened surface.    
     
     
         16 . A two-component developer comprising: 
 a toner material; and    a carrier,    wherein the toner material comprises the toner according to  claim 1  as a toner base, and 1 to 6 parts by weight of inorganic fine powder having an average particle size of 6 nm to 200 nm is added to 100 parts by weight of the toner base, and    wherein the carrier comprises magnetic particles as a core material, and at least a surface of the core material is coated with a fluorine modified silicone resin containing an aminosilane coupling agent.    
     
     
         17 . The two-component developer according to  claim 16 , wherein 0.5 to 2.5 parts by weight of the inorganic fine powder having an average particle size of 6 nm to 20 nm, and 0.5 to 3.5 parts by weight of the inorganic fine powder having an average particle size of 20 nm to 200 nm are added to 100 parts by weight of the toner base.  
     
     
         18 . The two-component developer according to  claim 16 , wherein 0.5 to 2.5 parts by weight of the inorganic fine powder having an average particle size of 6 nm to 20 nm and an ignition loss of 1.5 to 25 wt %, and 0.5 to 3.5 parts by weight of the inorganic fine powder having an average particle size of 20 nm to 200 nm and an ignition loss of 0.5 to 23 wt % are added to 100 parts by weight of the toner base.  
     
     
         19 . The two-component developer according to  claim 16 , wherein the carrier comprises 5 to 40 parts by weight of the aminosilane coupling agent per 100 parts by weight of the coating silicone resin.  
     
     
         20 . The two-component developer according to  claim 16 , wherein the carrier comprises 1 to 15 parts by weight of conductive fine powder per 100 parts by weight of the coating silicone resin.  
     
     
         21 . The two-component developer according to  claim 16 , wherein the carrier comprises 0.1 to 5.0 parts by weight of the coating silicone resin per 100 parts by weight of the core material.  
     
     
         22 . The two-component developer according to  claim 16 , wherein the fluorine modified silicone resin is a cross-linked fluorine modified silicone resin obtained by a reaction of an organosilicon compound containing a perfluoroalkyl gourp with polyorganosiloxane.  
     
     
         23 . The two-component developer according to  claim 22 , wherein the organosilicon compound containing a perfluoroalkyl group is at least one selected from the group consisting of CF 3 CH 2 CH 2 Si(OCH 3 ) 3 , C 4 F 9 CH 2 CH 2 Si(CH 3 )(OCH 3 ) 2 , C 8 F 17 CH 2 CH 2 Si(OCH 3 ) 3 , C 8 F 17 CH 2 CH 2 Si(OC 2 H 5 ) 3 , and (CF 3 ) 2 CF(CF 2 ) 8 CH 2 CH 2 Si(OCH 3 ) 3 .  
     
     
         24 . The two-component developer according to  claim 22 , wherein the polyorganosiloxane is at least one selected from Formula 1 and Formula 2.  
       
         
           
           
               
               
           
         
       
       (where R 1  and R 2  are a hydrogen atom, a halogen atom, a hydroxy group, a methoxy group, an alkyl group having a carbon number of 1 to 4, or a phenyl group, R 3  and R 4  are an alkyl group having a carbon number of 1 to 4 or a phenyl group, and m represents a mean degree of polymerization and is positive integers)  
       
         
           
           
               
               
           
         
       
       (where R 1  and R 2  are a hydrogen atom, a halogen atom, a hydroxy group, a methoxy group, an alkyl group having a carbon number of 1 to 4, or a phenyl group, R 3 , R 4 , R 5 , and R 6  are an alkyl group having a carbon number of 1 to 4 or a phenyl group, and n represents a mean degree of polymerization and is positive integers)  
     
     
         25 . The two-component developer according to  claim 22 , wherein the fluorine modified silicone resin is a cross-linked fluorine modified silicone resin obtained by a reaction of 3 to 20 parts by weight of the organosilicon compound containing a perfluoroalkyl gourp with 100 parts by weight of the polyorganosiloxane.  
     
     
         26 . An image forming apparatus comprising: 
 a plurality of toner image forming stations, each of which comprises an image support member, a charging member for forming an electrostatic latent image on the image support member, and a toner support member, and    an endless transfer member,    wherein the apparatus has a transfer system including a primary transfer process and a secondary transfer process,    in the primary transfer process, an electrostatic latent image formed on the image support member is made visible by development with a toner comprising:    colored particles; and    an external additive,    the colored particles produced by heating and aggregating a mixture that includes a resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, so that at least part of the first resin particles is melted,    wherein the colored particles have a finely roughened surface; or the two-component developer according to  claim 16 , and a toner image obtained by the development of the electrostatic latent image is transferred to the transfer member that is in contact with the image support member,    the primary transfer process is performed continuously in sequence so that a multilayer toner image is formed on the transfer member, and    the secondary transfer process is performed by collectively transferring the multilayer transfer image formed on the transfer member to a transfer medium, and    wherein the transfer system satisfies a relationship expressed by        d 1 /v ≦0.65 (sec)    where d1 (mm) is a distance between a first primary transfer position and a second primary transfer position, or between the second primary transfer position and a third primary transfer position, or between the third primary transfer position and a fourth primary transfer position, and v (mm/s) is a circumferential velocity of the image support member.    
     
     
         27 . An image forming apparatus comprising: 
 a plurality of toner image forming stations, each of which comprises an image support member, a charging member for forming an electrostatic latent image on the image support member, and a toner support member,    wherein the apparatus has a transfer system including a transfer process in which an electrostatic latent image formed on each of the image support members is made visible by development with a toner comprising:    colored particles; and    an external additive,    the colored particles produced by heating and aggregating a mixture that includes a resin particle dispersion in which first resin particles are dispersed and a pigment particle dispersion in which pigment particles are dispersed, so that at least part of the first resin particles is melted,    wherein the colored particles have a finely roughened surface; or the two-component developer according to  claim 16 , and toner images obtained by the development of the electrostatic latent images are transferred successively to a transfer medium, and    wherein the transfer system satisfies a relationship expressed by        d 1 /v≦ 0.65 (sec)    where d1 (mm) is a distance between a first transfer position and a second transfer position, or between the second transfer position and a third transfer position, or between the third transfer position and a fourth transfer position, and v (mm/s) is a circumferential velocity of the image support member.    in the primary transfer process, an electrostatic latent image formed on the image support member is made visible by development with the toner according to  claim 1  or the two-component developer according to  claim 16 , and a toner image obtained by the development of the electrostatic latent image is transferred to the transfer member that is in contact with the image support member,    the primary transfer process is performed continuously in sequence so that a multilayer toner image is formed on the transfer member, and    the secondary transfer process is performed by collectively transferring the multilayer transfer image formed on the transfer member to a transfer medium, and    wherein the transfer system satisfies a relationship expressed by        d 1 /v≦ 0.65 (sec)    where d1 (mm) is a distance between a first primary transfer position and a second primary transfer position, or between the second primary transfer position and a third primary transfer position, or between the third primary transfer position and a fourth primary transfer position, and v (mm/s) is a circumferential velocity of the image support member.    
     
     
         27 . An image forming apparatus comprising: 
 a plurality of toner image forming stations, each of which comprises an image support member, a charging member for forming an electrostatic latent image on the image support member, and a toner support member,    wherein the apparatus has a transfer system including a transfer process in which an electrostatic latent image formed on each of the image support members is made visible by development with the toner according to  claim 1  or the two-component developer according to  claim 16 , and toner images obtained by the development of the electrostatic latent images are transferred successively to a transfer medium, and    wherein the transfer system satisfies a relationship expressed by        d 1 /v≦ 0.65 (sec)    where d1 (mm) is a distance between a first transfer position and a second transfer position, or between the second transfer position and a third transfer position, or between the third transfer position and a fourth transfer position, and v (mm/s) is a circumferential velocity of the image support member.